The present invention relates to the separation of biological cells, small dieletric bodies or large molecules suspended in a liquid.
Conventional chemical processes for purification, such as crystallization and distillation, are unsuitable for biological materials. Biological molecules are difficult to separate because they consist of delicate and chemically similar compounds present in dilute suspensions. The task of separating biological cells is even more difficult because they are fragile and tend to aggregate.
It would be desirable to provide an improved technique for separation of large molecules, such as DNA. Such a technique would facilitate clinical diagnosis of pathogenic organisms by determination of the distribution of chromosome-sized DNA molecules, the location of genes responsible for genetic defects by preparing maps of megabase pair DNA regions, and molecular genetic analysis of genomes.
It would further be desirable to provide an improved technique for separating biological cells and subcellular orgonelles. Such a technique would be generally useful in the isolation of certain cell types for clinical evaluation and culture, and in particular, in the isolation of hybird cells from parent cells in the fields of immunology and agriculture, and the isolation of cells containing the end products of fermentation processes, as well as other genetic engineering applications.
Prior techniques for separating biological cells or similar small dielectric bodies have included electrophoresis, centrifugation, dielectrophoresis, filtering, and magnetophoresis. See for example "Methods of Cell Separation", Vol. 1, 2, 3, N. Catsimpoolas, Plenum Press, New York, 1977. U.S. Pat. No. 4,326,026 discloses a flow activated technique for separating live X and Y sperm cells. U.S. Pat. No. 4,578,168 discloses a dielectrophoresis technique for fusing line cells to form viable hybridomas which may be used in the production of monoclonal antibodies.